Zinc mercaptobenzothiazole and ferric dimethyl dithiocarbamate fungicidal composition



fail-1 a Patented Oct. 21, 1952 zmoms ca 'rjontnzormiaz AND RIC IMETHYL DITHIQGATQ E clai 'coM ou t e, Carmel, N. Y., asslgnor to Incorporated, New York,

n of New York Dr w... ,r- A p t rsh 28, 1,949,

gserial No. 84,0021

Qlaim, (Cl. 167-22) fl is nveat p which a e in as n It is Kno i he -t hat term ldimetey sses s irliuasieiqa 1 M amfltepess erties, and it is the object of the p'rese o provide mew wmngsitiea of matter hams such properties and containing such dithiocarbamate and another material. The new composiiions ossess nhaWedh ility that 129 fungicidal properties greater than would e expected item th lprgnext f the constituents of such compositions.

The aforementioned object i accomplished in accordance-with the present i invention by providingtacomposition having-utility as a fungicide and containing as .actiye ingredients ferric dimethyl clithiocarbamate, a compound having the structural formula and zinc mercaptobenzothiazole, a compound having the structural formula Ferric dimethyl dithiocarbamate may be prepared by procedures which are well understood, for example, by reacting in aqueous solution a suitable alkali metal dimethyl dithiocarbamate (e. 3.,

with a water-soluble ferric salt (e. g., ferric chloride, nitrate or sulfate) to precipitate the ferric dimethyl dithiocarbamate.

The zinc salt of mercaptobenzothiazole may be similarly prepared, for example, by reacting in aqueous solution the sodium salt of mercaptobenzothiazole with a water-soluble zinc salt (e. g., the chloride, sulfate or nitrate) to precipitate zinc mercaptobenzothiazole.

In comparing the fungicidal efiectiveness of omresitionsematte m mva ese which 1-2 the mixtures of the present inventionyvith the efiectiveness of the separate active ingredients thereof, there was usegla method which has been found to be easily r'eproduced, which gives relatively constant results without involving cum-bersome techniques, and which has been applied to a-humber of-fu ngi with equal efficiencies demone l The method consisted of a test tub dilution,

using .9. nutrient #salt solution (composed of 40 grams of dextrose, 2 grams of asp'aragine, 05

gram of --potassium dihyd-rogen phosphate, 0. 25 gram of MESO4.7H2O, 0.0003'gram of thiamine chloride add 13000 le; distilled water a spore suspension of Aspergill us niger (made from mature, healthyculture tubesby-washing a given tube-withdouralidiitrtsof 5 ml. of distilled water and thereafterdiluting the washingsw-ith distilled protectant (fungicide).

The dilution test was performed by first adding to a test tube 1 ml. of the nutrient solution, after which 3.50 ml. of the spore suspension was added and the mixture was agitated. The protectant was solubilized in a minimum amount of a suitable non-reactive solvent (water or a mixture of water and acetone) suspended where necessary by constant agitation. In testing the effectiveness of various protectants, varying amounts: thereof were added to a given test tube containing the 1 ml. of nutrient solution and the 3.50 ml. of the spore suspension, the final volume of the mixture of nutrient solution, spore suspension and protectant solution in a given test tube being 5 ml. The test tube containing the 5 ml. total mixture was then agitated to attain homogeneity, and by means of a 1 ml. pipette (graduated in 1/100 ml. subdivisions) drops of the mixture were placed on chemically cleaned microscope slides in triplicate.

These slides were placed in large Petri dishes mm. x 20 mm.) containing a quantity of distilled water and a. glass rod support which held the slides above the surface of the water. Petri dish covers were placed on the dishes and the spores were then incubated for 48 hours at 30: 1 C. The presence of the water in the Petri dishes assured high humidity, thereby preventing the test solutions from drying. At the end of the incubation period, the slides were removed from the Petri dishes and were examined microscopicallyf for signs of germination of the spores. Whereino spores had germinated, the protectant at the concentration employed was considered to be completely fungicidal or fungistatic.

The following table contains data obtained using the method just described, the data concerning the relative fungicidal activities of various compositions falling within the scope of the present invention withthe effectiveness of ferric dimethyl dithiocarbamate and' zinc mercaptobenzothiazole alone:

Active Fungicidal Ingredients Minimum p. p. m. of active ingredients Weight percent Weight percent zinc for zero germination ferric dimethyl rnercaptobenzoin dilution test dithiocarbamate thiazole The preceding table illustrates various compositions falling Within the scope of the present invention, such compositions being prepared from ferric dimethyl dithiocarbamate and zinc mercaptobenzothiazole.

As is shown by the data contained in the table, the relative proportions of the active ingredients contained in the fungicidal composition maybe varied widely, nevertheless producing mixtures characterized by advantageous properties. It is preferred, however, that the fungicidal composition contain from 25 to 50% by weight'of the zinc salt or from 1 to 5% of the zinc salt, based upon the weight of active ingredients contained in the composition.

The mixtures of the present invention are not restricted in their advantage to the prevention of growth of Aspergz'llus niger. Thus, they have also been used to advantage in preventing the germination of species of trichoderma and penicillium; Q

The composition of the present invention may conveniently be used in the form of a conventional agricultural fungicide spray, for example,

suspended in Water. Also, the composition may be used in the form of a dust prepared, for example, by first preparing an intimate mixture of the active ingredients and thereafter admixing such mixture with a conventional inert, solid diluent, such as lime, bentonite, talc, pyrophyllite, gypsum, chalk, silica, etc.

Iclaim: v

A composition of matter suitable for use as a fungicide, the active fungicidal ingredients of such composition comprising zinc mercaptobenzothiazole and f erricdimethyl dithiocarbamate in such proportions that the weight of zinc mercaptobenzothiazole is'within the range from 25 to per cent, based upon theweight of zinc mercaptobenzoth'iazole and ferric dimethyl dithiocarbamate.

ALBERT A. SOMERVILLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS S OTHER REFERENCES Goldworthy et al. J. Agr. Res. vol. 66, No. 7, pages 277 to 291, April 1, 1943. 

